Method of making cutting dies



Jan. 11, 1966 H. BIEN 3,228,263

METHOD OF MAKING CUTTING DIES Filed May 11, 1964 I6. I. FIG. 2.

INVENTOR HOWARD L- BIEN l4" FIG. l2.

ATTORNEY.

United States Patent 3,228,263 METHOD OF MAKING CUTTING DIES Howard L.Bien, Forest Hills, N.Y., 'assignor to Production Technologies, lino,Plainview, N.Y., a corporation of New York Filed May 11, 1964, Ser. No.366,555 6 Claims. (Cl. 76-107) The present invention relates to a methodof making cutting dies to be use in working on sheet material and ispreferably designed, though not necessarily, for the production of alimited number of pun-chings of an irregular outline.

A method of making a device for punching sheet metal has been proposedbefore which comprises the steps of cutting an opening in a die blockhaving the contour of the desired punching and then bending blade meansin strip form to make cutting edges and fitting them around the insideof the opening of the die block. A smaller block of the same contour ispressed thereafter into the space enclosed by the blades, a punch plateis fastened to a base plate and the cutting edges of the blades arepressed into the punch plate to mark off the desired contour thereon.The marked punch plate is then removed from the base plate and trimmedto the marked outline of the contour and finally the trimmed punch plateis fastened to the base plate. This method brought insufficient resultsonly, because it provided for the thickness of the sheet metal by trialand error only.

Another method of making cutting dies has been disclosed in applicantsown prior Patent No. 2,791,134, dated May 7, 1957, which comprises thesteps of cutting out of a block a center piece having an inner and outercontour, respectively, of the article to be punched out of sheetmaterial, whereupon blade means are fitted around the center piece andthe latter is reassembled in the block with the blade means projectingfrom the block and clamped therebetween. A layer of spacing material ofa thickness complementary to the thickness of the sheet material to beworked is then applied on the inside of the projecting portion of theblade means. Material, as for instance plastic material, is then pouredin its liquid state into the space defined by the top face of the centerpiece and the layers of spacing material to form a punch member of acontour complementary to the center piece, the difference in sizebetween the punch member and the center piece being determined by thethickness of the sheet material to be punched. Finally, the punch memberand the clamped blade means are mounted on oppositely disposedsupporting members to operate as male and female die members,respectivley.

It is one object of the present invention to provide a method of makingcut-ting dies, which constitute a further development of the methoddisclosed in said Patent No. 2,791,134 and which permits an appreciablygreater number of punchings and is subjected to less wear during theoperation of the cutting die.

It is another object of the present invention to provide a method ofmaking cutting dies which comprises the steps of cutting out of a blocka center piece having an inner and outer contour, respectively, of thearticle to be punched out of material, whereupon preferably steelsections are fitted around the center piece and the latter isreassembled in the block with the steel sections projecting from theblock and retained therebetween. A releasing substance is applied,preferably by spraying, to the inside of the projecting portions of thesteel sections, in order to permit removal of the male body poured intothe block. Material, as for instance plastic material, is then poured inits liquid state int-o the space defined by the top face of the centerpiece and the steel sections to form a center 3,228,2fi3 Patented Jan.11, 1966 member of said poured material which solidifies atroomtemperature or at a lower or higher temperature, depending upon thedesired speed of curing. The center member is then removed and separatedfrom the steel sections, to be put into a frame larger than the centermember. For the purpose of providing exact die clearance and alsoallowance for shrinkage of material, a layer of spacing material, as forinstance plastic, is applied to the inner and outer surface,respectively, of the center member. Material of the same nature as thefirst used material, as for instance plastic material, is then pouredinto the frame to obtain a female member complementary to the malecenter member, considering the spacing layer. The male center member isthen removed from the female member and tool steel in its liquid stateis poured into the female member. Upon cooling, the tool steel centerbody is removed from the female member and applied to a support mountedto operate as a male punch, while the mounted steel sections aredisposed opposite the male punch to operate as a female die.

With these and other objects in View, which will become apparent in thefollowing detailed description, the present invention will be clearlyunderstood in connection with the accompanying drawing, in which:

FIGURE 1 is a perspective exploded view of a wood block and itscomplementary center piece;

FlG. 2 is a top perspective view of the wood block, the center piecebeing reinserted, together with tool steel sections;

FIG. 3 is a top perspective view of the wood block with its center pieceand the tool steel sections therebetween, and a punch molded therein;

FIG. 4 is a section along the lines 44 of FIG. 3;

FIG. 5 is a top perspective view of the molded punch upon removalthereof from the blade means and surrounded by a frame;

FIG. 6 is a section along the lines 6-6 of FIG. 5;

FIG. 7 is a section, similar to that of FIG. 6, of the frame afterpouring material into the frame surrounding the molded punch;

FIG. 8 is a top perspective view of the female mold after removing themolded punch therefrom;

FIG. 9 is a section along the lines 9-9 of FIG. 8;

FIG. 10 is a top perspective view of the female mold indicatingschematically the pouring of tool steel in its liquid state into thefemale mold;

FIG. 11 is a top perspective view of the tool steel punch;

FIG. 12 is a top perspective view of the male punch member mounted on apress plate;

FIG. 13 is a bottom perspective View of the female die member mounted ona press plate; and

FIG. 14 is a section along the lines 1414 of FIG. 12 indicating thealignment and cooperation of the male punch member with the female punchmember.

Referring now to the drawing, the present method provides at first theproduction of a provisional male punch member, as well as a female diemember, and the provisional male punch member is used, as set forthbelow in greater detail, for the production of the tool steel male punchmember, which permits for practical purposes an unlimited number ofstampings.

The method according to the present invention provides at first a woodblock 1 on which the outline of the shape to be punched out of sheetmaterial, bars, flat stock, or the like is marked. A centerpiece 2 isthen cut out from the wood block 1 along the marked lines and removedfrom the wood block 1. Tool steel sections 3 are fitted to the sidefaces of the centerpiece 2, whereupon the centerpiece 2 is insertedagain into the wood block 1 together with the tool steel sections 3. Inorder to bring about a good fit of the tool steel sections 3 between thecenterpiece 2 and the wood block 1 it is preferable to use a saw blade(not shown) for cutting out the centerpiece 2, which saw blade has athickness equivalent to that of the steel sections 3, or the saw blademay have lesser thickess, in which case by example a press fit or anyother suitable means can be used.

Upon reassembling the centerpiece 2 with the tool steel sections 3 intothe wood block 1, the tool steel sections 3 project above the top faceof the wood block 1 and the centerpiece 2, respectively, and thisassembled unit is used to produce an intermediate or provisionalcomplementary male punch member 5. A releasing substance is applied,preferably by spraying to the inside of the projecting portions of thesteel sections, in order to permit removal of the male body poured intothe block. The production of the intermediate male punch member isbrought about by pouring a suitable material, which may be an alloy, aplastic or any other suitable material having characteristics, whichmakes it suitable for the present purpose, on top of the centerpiece 2,whereby the tool steel sections 3 constitute the lateral limitationsduring the pouring of the material. The internal shapes thus formed inthe mold may be used as transfer means. The intermediate male punchmember may solidify at room temperature or at a lower or highertemperature, depending upon the desired speed of curing.

As indicated in FIG. 5 of the drawing, the intermediate male punchmember 5 is placed into a frame 6 which surround the member 5. terial ofwax sheeting, steel stripping, cold poured ceramic, fiber glass, or anyother suitable material, is applied to the outer faces of theprovisional punch member 5, in order to provide die clearance as well asallowance of shrinkage and substantially the same material used forpouring in the forming of the provisional male punch member 5 is alsoused for the pouring of an intermediate female die member 8, as clearlyshown in FIGS. 7, 8' and 9. Upon cooling of the intermediate female diemember 8, the male punch member 5 is removed therefrom.

The female die member 8 is used as a mold for producing the final malepunch member 10 which is formed by pouring tool steel in its liquidstate, as schematically shown in FIG. 10, where the liquid tool steel ispoured from a ladle 11, to obtain the male punch member 10, as shown inFIG. 11. Prior to the pouring of liquid steel, a releasing substance maybe applied to the inner faces of the female die member 8, yet suchsubstance can be dispensed With.

FIGS. 12 to 14 disclose the mounting of the male punch member 10 and thefemale die member 1, for instance in a press 12. In FIG. 12 the malepunch member 10 is preferably mounted on a steel plate 13. The femaledie 1 with the tool steel sections 3 is also preferably mounted on aplate 14 and opposite the male punch member.

While I have disclosed one embodiment of the present invention, it is tobe understood that this embodiment is given by example only and not in alimiting sense, the

A thin layer 7 of spacing mascope of the present invention beingdetermined by the object-s and the claims.

I claim: 1. A method of making cutting dies comprising the 5 steps ofcutting out of a block a centerpiece having the inner and outer contourof an article to be punched out of fiat material, fitting tool steelsections around said centerpiece and reassembling said centerpiece insaid block with said tool steel sections projecting from said block andretained therebetween to form a first female die member, pouringmaterial in its liquid state into the space defined by the top face ofsaid centerpiece and said tool steel sections to form a first punchmember of a contour complementary to said centerpiece, surrounding saidfirst punch member by a frame, pouring material into the space definedbetween said frame and said first punch member, to produce a secondfemale die member, pouring tool steel in its liquid state into saidsecond female die member to produce a second male punch member, removingsaid second male punch member from said second female die member. 2. Themethod, as set forth in claim 1, wherein said first of said female diemembers is mounted for the punching operation. 3. The method, as setforth in claim 1, which includes the step of applying a releasingsubstance to the inside of the projecting portion of said tool steelsections, prior to said step of pouring material into the space definedby the top face of said centerpiece and said tool steel sections. 4. Themethod, as set forth in claim 1, which includes the step of applying areleasing substance to the inside of said second female die member priorto said step of pouring tool steel into second female die member. 5. Themethod, as set forth in claim 1, which includes the step of applying alayer of spacing material, of a thickness 4 complementary to the desireddie clearance related to the thickness of the material to be worked, aswell as allowance of shinkage, to the outer face of said first punchmember. 6. The method, as set forth in claim 1, which includes the stepof mounting said second male punch member and one of said female diemembers in opposite arrangement for the punching operation.

No references cited.

GRANVILLE Y. CUSTER, JR.,' Primary Examiner,

1. A METHOD OF MAKING CUTTING DIES COMPRISING THE STEPS OF CUTTING OUTOF A BLOCK A CENTERPIECE HAVING THE INNER AND OUTER CONTOUR OF ANARTICLE TO BE PUNCHED OUT OF FLAT MATERIAL, FITTING TOOL STEEL SECTIONSAROUND SAID CENTERPIECE AND REASSEMBLING SAID CENTERPIECE IN SAID BLOCKWITH SAID TOOL STEEL SECTIONS PROJECTING FROM SAID BLOCK AND RETAINEDTHEREBETWEEN TO FORM A FIRST FEMALE DIE MEMBER, POURING MATERIAL IN ITSLIQUID STATE INTO THE SPACE DEFINED BY THE TOP FACE OF SAID CENTERPIECEAND SAID TOOL STEEL SECTIONS TO FORM A FIRST PUNCH MEMBER OF A CONTOURCOMPLEMENTARY TO SAID CENTERPIECE, SURROUNDING SAID FIRST PUNCH MEMBERBY A FRAME, POURING MATERIAL INTO THE SPACE DEFINED BETWEEN SAID FRAMEAND SAID FIRST PUNCH MEMBER, TO PRODUCE A SECOND FEMALE DIE MEMBER,POURING TOOL STEEL IN ITS LIQUID STATE INTO SAID SECOND FEMALE DIEMEMBER TO PRODUCE A SECOND MALE PUNCH MEMBER, REMOVING SAID SECOND MALEPUNCH MEMBER FROM SAID SECOND FEMALE DIE MEMBER.